Bit with co-radial cutting profile and cutting element

ABSTRACT

A cutting tool may include multiple blades extending from a bit body, and multiple cutting elements coupled to the blades. First cutting elements and a second cutting element coupled to the blades may collectively define a cutting profile of the bit. The second cutting element may be substantially larger than at least some of the first cutting elements and may substantially define a nose region of the cutting profile.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of, and priority to, U.S. PatentApplication Ser. No. 61/976,046, filed Apr. 7, 2014 and titled “BIT WITHCO-RADIAL CUTTING PROFILE AND CUTTING ELEMENT,” which application isincorporated herein by this reference in its entirety.

BACKGROUND

A wellbore may be extended into a subterranean formation by rotating adrill bit at the end of a drill string. While applying weight via thedrill string, the drill bit engages and removes material from theformation. Removal of the material may occur by abrasion, fracturing,shearing, or other manners. The diameter of the wellbore may beproportional or otherwise related to the diameter of the cutting profileof the drill bit. Thus, larger diameter drill bits are utilized inlarger diameter wellbores, and smaller diameter drill bits are utilizedin smaller diameter wellbores. However, as the diameter of a wellboredecreases, the availability of certain types of cutting elements (e.g.,polycrystalline diamond compact (“PDC”) cutters) may be limited. Thesefactors may also restrict cutting element placement, such as may be dueto manufacturing tolerances, physical interferences, and other factors.

Similar drill bits may also be utilized to remove scale from within awellbore. In such implementations, scale builds from the outside of thewellbore or within a tubular in the wellbore. The amount of scale mayvary along the length of the wellbore, thereby changing the shear,impact, or other forces experienced by the drill bit.

SUMMARY

Embodiments of the present disclosure may relate to a cutting tool thatincludes multiple blades extending from a bit body. Two different typesof cutting elements may be located on the blades. The second type ofcutting elements may substantially define a nose region of the cuttingprofile and may be substantially larger than the first type of cuttingelements. The two different cutting elements may differ by size, shape,construction, materials, or in other manners.

In some embodiments, an apparatus that may be used for a drilling,milling, reaming, scaling, or other operation may include a bit bodywith multiple blades coupled thereto. Cutting elements may be positionedon a corresponding one of the blades and may define a cutting profilewith a nose region between a cone region and a gage region. The noseregion may be nearest a central axis of the bit body, and the gageregion may be furthest from the central axis. The nose region may beshaped to have a radius substantially equal to, and potentially definedby, a first type of cutting element. The first type of cutting elementmay have a diameter or size substantially different than a diameter orsize of a second type of cutting element located at the cone and/or gageregions of the cutting profile.

According to some embodiments, a method includes urging a bit toward adownhole end of a wellbore and dislodging material from the wellbore byrotating the bit. The bit used to dislodge material may include multiplecutting elements that collectively define a cutting profile with a noseregion between cone and gage regions. A radius of the nose region may besubstantially equal to, and co-radial with, a first set of cuttingelements. A second set of cutting elements may be positioned at the coneand gage regions and may have a smaller diameter than the first set ofcutting elements.

A method for designing a bit is also described, and may includeselecting a first size of a cutting element. A second size of cuttingelements may also be selected to be different than the first size. Afterselecting the first size of a cutting element, a cutting profile can becreated with a nose region and potentially other regions. The noseregion may be created to have a nose radius substantially equal to aradius of the first size of a cutting element. Cutting elements of thedifferent sizes can be arranged on multiple blades of a bit having thecutting profile to position the first size of cutting element co-radialwith the nose region and the second size of cutting elements in theother regions of the cutting profile.

This summary is provided to introduce a selection of concepts that arefurther described in the description that follows. This summary is notintended to identify key or essential features of the claimed subjectmatter, nor is it intended to be used as an aid in limiting the scope ofthe claimed subject matter. Accordingly, additional aspects of thepresent disclosure are set forth in the description that follows, and/ormay be learned by a person having ordinary skill in the art by readingthe materials herein and/or practicing the principles described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be understood from the following detaileddescription when read with the accompanying figures. While the drawingsillustrate certain components at a relative scale that may be used insome implementations of such embodiments, it is emphasized that, inaccordance with the standard practice in the industry, various featuresare not drawn to scale for other implementations or embodiments. In somedrawings, the dimensions of the various features may be increased orreduced for clarity of discussion.

FIG. 1 is a schematic illustration of a portion of a drilling systemaccording to one or more aspects of the present disclosure.

FIG. 2 is a perspective view of a bit according to one or more aspectsof the present disclosure.

FIG. 3 is a section view of a portion of a bit, with cutting elementsdefining a cutting profile and presented in a rotationally aggregatedview, according to one or more aspects of the present disclosure.

FIG. 4 is a schematic, rotationally aggregated view of cutting elementsdefining a portion of a bit profile according to one or more aspects ofthe disclosure.

FIG. 5 is a schematic, rotationally aggregated view of cutting elementsdefining a portion of a bit profile according to one or more aspects ofthe present disclosure.

FIG. 6 is a perspective view of a portion of a bit according to one ormore aspects of the present disclosure.

FIG. 7 is a perspective view of multiple cutting elements as they may bepositioned on a bit, according to one or more aspects of the presentdisclosure.

FIG. 8 is a schematic, rotationally aggregated view of cutting elementsdefining a portion of a bit profile according to one or more aspects ofthe present disclosure.

FIG. 9 is a flow-chart diagram of a method for designing a bit accordingto one or more aspects of the present disclosure

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides manydifferent embodiments, or examples, for implementing different featuresof various embodiments of the present disclosure. Specific examples ofcomponents and arrangements are described to simplify the presentdisclosure. These are merely examples, and are not intended to belimiting. In addition, the present disclosure may repeat referencenumerals in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

FIG. 1 is a schematic view of a portion of a drilling system accordingto one or more aspects of the present disclosure. Depicted componentsinclude a wellsite 10, a rig 15, and a bottom-hole assembly (“BHA”) 20suspended from the rig 15 in a wellbore 12 via a drill string and/oranother string of tubular members 25. The BHA 20 may include or becoupled to a bit 30 at its lower or distal end, which may be operable toadvance into a formation 35 and form or extend the wellbore 12. The bit30 may be, include, form a portion of, or otherwise have one or moreaspects in common with the example bit implementations described hereinand/or other bits within the scope of the present disclosure (e.g.,drill bits, milling bits, underreamers, etc.).

The string of tubular members 25 may be rotated by a rotary table 40that engages a kelly (not shown) at an upper end of the string oftubular members 25. The string of tubular members 25 may be suspendedfrom a hook 45 attached to a traveling block (not shown) through thekelly and a rotary swivel 50 that permits rotation of the string oftubular members 25 relative to the hook 45.

The rig 15 is depicted as a land-based kelly platform and derrickassembly utilized to form the wellbore 12 by rotary drilling; however, aperson having ordinary skill in the art will appreciate that one or moreaspects of the present disclosure may also find application in otherdownhole implementations, including off-shore rigs, and is not limitedto land-based rigs. Moreover, the one or more aspects of the presentdisclosure may be used in connection with different types of land-basedrigs (e.g., electrical, hydraulic, conventional, coil tubing, singledrill pipe, double drill pipe, etc.) and different types of off-shorerigs (e.g., fixed platform, floating production, tension leg, subsea,compliant tower, sea star, SPAR platform, etc.). A person havingordinary skill in the art will also recognize in view of the presentdisclosure that one or more aspects of the present disclosure may beapplicable or readily adaptable for use with top drive systems in lieuof or addition to a rotary table 40.

Drilling fluid 55 may be stored in a reservoir 60 at the wellsite 10.The reservoir 60 may include a tank, a pit formed in the ground, someother type of storage, or a combination of the foregoing. The drillingfluid 55 may include so-called drilling mud, or any fluid suitable foruse within a drilling system. A pump 65 may be used to deliver drillingfluid 55 to the interior of the string of tubular members 25 via a portin the rotary swivel 50, thereby inducing the drilling fluid to flowdownward through the string of tubular members 25, as indicated in FIG.1 by directional arrow 70. The drilling fluid 55 may then exits viaports in the bit 30, and then circulate upward as indicated in FIG. 1 bydirection arrows 75, through an annulus defined between the outside ofthe string of tubular members 25 and the interior wall of the wellbore12. In this manner, the drilling fluid 55 may lubricate the bit 30,carry formation cuttings up to the surface, and be returned to thereservoir 60 for recirculation.

The BHA 20 may be positioned near the bit 30, perhaps within the lengthof several drill collars and/or other tubular members 25 from the bit30. The BHA 20 may include various components with various capabilitiesproviding steerability of the bit 30, and may be further operable tofacilitate the measuring, processing, or storing of information aboutthe BHA 20 and/or the subterranean formation 35. A telemetry device (notshown) may also be provided for communicating with one or morecomponents of surface equipment 14. Example surface equipment 14 mayinclude acquisition, control, automation, user interface, otherequipment, or some combination of the foregoing.

FIG. 2 is a perspective view of an example implementation of a bit 200according to one or more aspects of the present disclosure. The bit 200is illustrative of an example bit that may be used in a drilling,milling, coiled tubing, or other system, including within the drillingsystem illustrated in FIG. 1. The bit 200 may be a fixed-cutter or dragbit having a bit body 210. The bit body 210 may be integral with orotherwise coupled to a threaded connection 212, which is shown asextending from the bit body 210 for connecting the bit 200 to a drillstring, drill collar, drilling tubular, or other component (e.g., a BHAcomponent). In some implementations, the threaded connection 212 may beor include a pin (or male portion) of a threaded pin-box connection.Operations involving the bit 200 may include rotating the bit 200 in acutting direction 202 around a central axis 204.

A bit face 220 may support blades 230, 232, 234, 240, 242, and 244. Inthe illustrated embodiment, the bit face 220 may include or otherwisesupport primary blades 230, 232, and 234, as well as secondary blades240, 242, and 244. The primary blades 230, 232, and 234 may be angularly(i.e., azimuthally or circumferentially) offset from each other at aparticular angular or azimuthal orientation. Similarly, the secondaryblades 240, 242, and 244 may each be angularly and azimuthally offsetfrom each other, and in the illustrated embodiment are shown as beingangularly spaced between circumferentially adjacent pairs of the primaryblades 230, 232, and 234. The primary blades 230, 232, and 234 and thesecondary blades 240, 242, and 244 may extend generally radially fromthe bit face 220, as well as axially along a portion of the periphery ofthe bit 200. In some embodiments, the primary blades 230, 232, and 234may extend radially from the bit face 220 from a position at or near thebit axis 204, while the secondary blades 240, 242, and 242 may extendradially from the bit face 220 from a position that is radially offsetfrom the bit axis 204. As shown in FIG. 2, the primary blades 230, 232,and 234 may extend axially along the bit face 220 to a position at ornear the distal or downhole end of the bit 200. In some embodiments, thesecondary blades 240, 242, and 244 may not extend to the distal ordownhole end of the bit 200. Junk slots 222 may separate the primaryblades 230, 232, and 234 and the secondary blades 240, 242, and 244, andpermit the passage of drilling fluid and cuttings.

As shown in FIG. 2, one or more pockets 254 may be formed in eachprimary blade 230, 232, and 234 and/or in each secondary blade 240, 242,and 244. Cutting elements 250 and 252 may be positioned in acorresponding pocket 254 formed in the primary blades 230, 232, and 234and secondary blades 240, 242, and 244, and welded, brazed, press-fit,or otherwise coupled to the corresponding blade 230, 232, 234, 240, 242,or 244. In other embodiments the cutting elements 250 and 252 may beintegral with the corresponding blade 230, 232, 234, 240, 242, or 244,or may be coupled to the bit 200 in other manners that are within thescope of the present disclosure. The pockets 254 may fix the cuttingelements 250 and 252 in particular locations and orientations relativeto the bit body 210, in some embodiments. In other embodiments, thecutting elements 250 and 252 may be movable within a pocket 254. Forinstance, the pocket 254 (or the cutting elements 250 and 252) mayinclude a bearing element, or other similar element allowing the cuttingelements 250 and 252 to rotate within the pocket 254 and relative to thebit body 210. The cutting elements 250 and 252 may each be arranged, forexample, along or proximate a leading edge 236 of a corresponding one ofthe primary blades 230, 232, and 234 and the secondary blades 240, 242,and 244.

The cutting elements 250 and 252 may each be made of, or include, amaterial having sufficient hardness and other material properties to cutthrough the desired formation, cement, scale, or other material, or tomill through steel casing, packers, bridge plugs, tubulars, or otherdownhole tools. In one embodiment, the cutting elements 250 and/or 252may include a substrate including tungsten carbide, cobalt cementedtungsten carbide, and/or other materials, and a cutting layer includingpolycrystalline diamond, polycrystalline cubic boron nitride, othermaterials, or some combination of the foregoing. In FIG. 2, thesubstrate and cutting layers may collectively define a substantiallycylindrical cutting element 250 and/or 252. In other embodiments,however, the cutting elements 250 and/or 252 may have other shapes orconfigurations (e.g., domed or semi-round top, conical, frustoconical,lobed, ridged, etc.).

The cutting element 250 may be larger than the cutting elements 252 insome embodiments. For example, the cutting element 250 may have adiameter of thirteen (13) millimeters, and the smaller cutting elements252 may have a diameter of nine (9) millimeters. Other dimensions arealso within the scope of the present disclosure, including withoutlimitation the examples described below in Table 1—Cutting Element SizeCombinations.

TABLE 1 Cutting Element Size Combinations Diameter of cutting element250 11 11 13 16 19 (mm) Diameter of cutting elements 252 6 9 6 11 11(mm) Size Difference (%) 83% 22% 117% 45% 73% Size Difference 2 1 3 2 3(# of standard sizes)

As also shown in Table 1, the size difference between the diameters ofthe cutting elements 250 and 252 may range between twenty-two percent(22%) and one-hundred seventeen percent (117%). However, other sizecombinations within the scope of the present disclosure may have a sizedifference that ranges between fifteen percent (15%) and three hundredpercent (300%). In some embodiments, the larger cutting elements 250 mayhave a diameter that is at least four (4) millimeters larger thediameter of at least some of the smaller cutting elements 252. In otherembodiments, the size difference may be greater or less than four (4)millimeters.

The example sizes provided above in Table 1 may be industry-standardsizes for the oil and gas industry (e.g., six (6) millimeters, nine (9)millimeters, eleven (11) millimeters, thirteen (13) millimeters, sixteen(16) millimeters, nineteen (19) millimeters, and twenty-two (22)millimeters), although custom or proprietary sizes may also be used inembodiments of the present disclosure. As shown, the size differencebetween standard sizes of cutting elements may range between one (1) andthree (3) standard sizes. Other size differences are also contemplated.For instance, a cutting element 250 may be four (4) or more standardsizes larger than the cutting elements 252. In some embodiments, acutting element (e.g., larger cutting element 250) may be“substantially” larger than another cutting element (e.g., smallercutting element 252) of a bit. As used herein with reference to relativesizes of cutting elements, sizes of cutting elements are considered tobe “substantially” different when one cutting element has a diameterthat is 25% larger than the diameter of the other cutting element, orwhen one cutting element is at least two (2) industry-standard sizessmaller or larger than another cutting element.

FIG. 3 is a schematic view of the bit 200 as it would appear with thecutting elements 250 and 252 rotated into an aggregated profile view. Inother words, the profile view of the bit 200 as shown in FIG. 3 maydepict a position of each cutting element 250, 252 from each primaryand/or secondary blade (e.g., blades 230, 232, 234, 240, 242, and 244 ofFIG. 2), as if each blade was positioned at the same azimuth at the sametime. Such view also depicts a cutting profile 305 (depicted in FIG. 3by a heavy dark line) collectively formed by an outermost edge 258 ofthe cutting element 250 and outermost edges 256 of the cutting elements252.

The cutting profile 305 may include a cone region 310, a nose region320, a shoulder region 330, a gage region 340, other regions, or acombination of the foregoing. As shown in FIG. 3, the cone region 310may be radially nearest to the bit axis 204, and the gage region 340 maybe radially furthest from the bit axis 204. The nose region 320 mayprovide a transition from the cone region 310 to the shoulder region330, or to the gage region 340 if no shoulder region 330 exists. Theshoulder region 330 may be included so that the transition between thenose region 320 and the gage region 340 is less abrupt. The gage region340 may define the diameter or gage of the bit 200, and therefore thewellbore, lateral borehole, casing window, or other openingdrilled/milled by the bit 200.

In the example implementation shown in FIG. 3, the outermost edges 256of four (4) smaller cutting elements 252 may define the cone region 310,the outermost edge 258 of the larger cutting element 250 may define thenose region 320, the outermost edges 256 of six (6) smaller cuttingelements 252 may define the shoulder region 330, and the outermost edges256 of two (2) smaller cutting elements 252 may define the gage region340. As will be understood by a person having ordinary skill in the artin view of the present disclosure, the boundaries of the cone region310, the nose region 320, the shoulder region 330, and the gage region340 are not precisely delineated on the bit 200, but are insteadapproximate, and are herein identified relative to one another for thepurpose of better describing the distribution of the cutting elements250 and 252 over the bit face 220. Generally, the cone region 310, theshoulder region 330, and the gage region 340 may each be defined by theoutermost edges 256 and may number as few as two (2) cutting elements252, or as many as thirty (30) cutting elements 252.

It is also noted that, within each region (310, 320, 330, and 340), the“number” of cutting elements 250 and 252 whose outermost edges 258 and256 define the corresponding region may represent the actual number ofcutting elements 250 and 252 distributed among the blades (e.g., blades230, 232, 234, 240, 242, and 244 of FIG. 2) within that region or, asshown in the view in FIG. 3, the number of distinct positions of cuttingelements 250 and 252. It should be appreciated in view of the disclosureherein, that the number of positions of cutting elements 250 and 252 maybe fewer than the number of actual cutting elements 250 and 252 definingor otherwise arranged or positioned in a corresponding region. Forinstance, some of the cutting elements 250 and 252 may have the sameradial and axial position on the bit 200, but may be located atdifferent azimuths on different ones of the blades (e.g., blades 230,232, 234, 240, 242, and 244 of FIG. 2). This convention also applies toembodiments shown in figures other than FIG. 3 and/or otherwise withinthe scope of the present disclosure.

As depicted in FIG. 3, the outermost edges 256 and 258 of the cuttingelements 252 and 250, respectively, may define the cutting profile 305in a scalloped or otherwise undulating fashion. Nonetheless, theorientations of the different regions (e.g., regions 310, 320, 330, and340) of the cutting profile 305 relative to each other and the bit axis204 may be described in general or approximate terms. For example, thecone region 310 may be substantially perpendicular to the bit axis 204.That is, whether the cone region 310 is scalloped, concave, convex, orotherwise non-linear, a best-fit linear approximation 312 (depicted inFIG. 3 by a dashed line) of the cone region 310 may be angularly offsetfrom the bit axis 204 by an amount ranging between eighty degrees (80°)and one hundred degrees (100°).

Such convention may also be utilized to describe the shoulder region 330as being substantially perpendicular to the cone region 310 and/or thebit axis 204. For example, although the shoulder region 330 may benon-linear, a best-fit linear approximation 332 (depicted in FIG. 3 by adashed line) of the shoulder region 330 may be angularly offset from thebest-fit linear approximation 312 of the cone region 310 by an amountranging between eighty degrees (80°) and one hundred degrees (100°). Thebest-fit linear approximation 332 of the shoulder region 330 may also orinstead be substantially parallel to the bit axis 204. For example, thebest-fit linear approximation 332 of the shoulder region 330 may beangularly offset from the bit axis 204 by less than ten degrees (10°).The gage region 340 may similarly be described as being substantiallyparallel to the bit axis 204 and/or substantially perpendicular to thecone region 310. That is, although the gage region 340 may benon-linear, a best-fit linear approximation of the gage region 340 maybe angularly offset from the bit axis 204 by less than ten degrees (10°)or offset from the cone region 310 by an amount ranging between eightydegrees (80°) and one hundred degrees (100°). In other embodiments,however, angular offsets between the cone region 310, shoulder region330, and gage region 340 may be more than ten degrees) (10° from beingparallel or perpendicular to each other, or relative to the bit axis204.

The nose region 320 may extend along a portion of the cutting profile305 aligned with the outermost edge 258 of the larger cutting element250, and between intersections with the outer edges 256 of the opposingsmaller cutting elements 252. In some embodiments, the nose region 320and the cutting element 250 may be co-radial, having the same radius 322and the same center point 324. In some implementations, the outermostedges 258 of multiple instances of the larger cutting element 250 (e.g.,carried by different ones of the primary blades 230, 232, and 234 ofFIG. 2) may collectively define the nose region 320. The multipleinstances of the larger cutting element 250 may have the same radial andaxial position on each blade, such that the nose region 320 is co-radialwith each of the larger cutting elements 250.

In the example implementation depicted in FIGS. 2 and 3, the outermostextents 256 of each cutting element 252 that doesn't define the coneregion 310 of the cutting profile 305 may collectively define theshoulder region 330 and the gage region 340, or at least a substantialportion thereof. The primary blades 230, 232, and 234 and/or thesecondary blades 240, 242, and 244 may carry the cutting elements 252whose outermost extents 256 define the shoulder region 330 and/or gageregion 340. The one or more primary blades 230, 232, and 234 that carrythe larger cutting element 250 may not carry the cutting elements 252that are closest to the nose region 320. Instead, the secondary blades240, 242, and 244, and/or one or more of the primary blades 230, 232,and 234 that do not carry the larger cutting element 250, may carry thecutting elements 252 that are closest to the nose region 320.

As shown in the example implementation depicted in FIG. 3, one or morechannels 360 may also extend between an interior passage 370 or bore ofthe bit 200 and outlet ports 380 on the bit face 220. Accordingly, fluid(e.g., drilling fluid) pumped to the bit 200 from the wellsite may exitthe outlet ports 380 via the channels 360 to lubricate the bit 200 andsubsequently carry any cuttings back to the surface.

FIG. 4 is a schematic view of another bit 400 shown in a rotationallyaggregated profile view, with cutting elements 250 and 252 collectivelydefining a cutting profile 405. Features of the bit 400, other than thecutting elements 250 and 252 and the cutting profile 405, are not shownin FIG. 4, although merely for the sake of clarity, as those skilled inthe art will readily understand with the benefit of the presentdisclosure that features and/or other aspects of other bits (e.g., thebit 200 of FIGS. 2 and 3) may be included, applicable, or readilyadapted for utilization in the bit 400 shown in FIG. 4.

The cutting profile 405 may comprise a cone region 410, a nose region420, and a gage region 440, with each being generally defined in thesame manner as similar regions are described above with respect to FIG.3. The portion of the outermost extent 258 of the larger cutting element250 that partially defines the cutting profile 405 may define the noseregion 420, or at least a substantial portion thereof (as describedherein), and in some embodiments the nose region 420 of the cuttingprofile 405 and the cutting element 250 may have substantially the sameradius 422 and perhaps the same center point 424. Thus, the nose region420 and the cutting element 250 may be co-radial in some embodiments.However, in other embodiments within the scope of the presentdisclosure, the tips, edges, or outer extents of additional cuttingelements may define a portion of the nose region 420. For example, theoutermost extent of multiple instances of the larger cutting element 250(carried by different ones of the primary blades) may define the noseregion 420, or at least a portion thereof. In other embodiments, thenose region 420 may be at least partially defined by one or more of thesmaller cutting elements 252.

The cutting element 250 may be considered to “substantially define” thenose region 420 when the cutting element 250 makes up at leastseventy-five percent (75%) of length of the nose region 420, with theremainder of the nose region 420 including one or more of the cuttingelements 250 and/or 252 in a different radial and/or axial position onthe bit 400. In some embodiments, the larger cutting element 250 may“substantially define” the nose region 420 when the larger cuttingelement 250 makes up at least ninety percent (90%) of the nose region420, with the remainder of the nose region 420 including one or more ofthe smaller cutting elements 252 or other larger cutting elements 250 ina different radial and/or axial position on the bit 400. In someembodiments, however, the nose region 420 may not be defined by cuttingelements other than one or more instances of the larger cutting element250 (e.g., each on a different blade). The nose region 420 may also beconsidered to have a radius “substantially equal” to the radius of thecutting element 250 when the radius of the cutting element 250 is withinat least twenty percent (20%) of the radius of the nose region 420.

In the example implementation depicted in FIG. 4, the outermost extents256 of the cutting elements 252 that don't define the cone region 410 ofthe cutting profile 405 may collectively define the gage region 440 ofthe cutting profile 405. The cutting elements 252 whose outermostextents 256 define the cone region 410 and/or the gage region 440 of thecutting profile 405 may be carried by multiple ones of the primary andthe secondary blades of the bit 400, and those that are closest to thenose region 420 of the cutting profile 405 may not be carried by theprimary blades that carry instances of the larger cutting element 250.

In the example implementation shown in FIG. 4, the outermost extents 256of two (2) cutting elements 252 may define the cone region 410 of thecutting profile 405, and the outermost extents 256 of at least three (3)cutting elements 252 may define the gage region 440. These numbers may,however, vary in other implementations within the scope of the presentdisclosure. Optionally, the larger cutting element 250 may have adiameter of thirteen (13) millimeters, and the smaller cutting elements252 may have a diameter of nine (9) millimeters, although otherdimensions are also within the scope of the present disclosure,including those set forth in Table 1 above, among others.

FIG. 5 is a schematic view of another bit 500, with cutting elements 250and 252 shown in a rotationally aggregated, profile view defining acutting profile 505. Features of the bit 500, other than the cuttingelements 250 and 252 and the cutting profile 505, are not shown in FIG.5, although merely for the sake of clarity, as those skilled in the artwill readily understand in view of the present disclosure that featuresand/or other aspects of other bits (e.g., the bits shown in FIGS. 2, 3,and 4) may be included, applicable, or readily adapted for utilizationin the bit 500 shown in FIG. 5.

The cutting profile 505 may comprise a cone region 510, a nose region520, and a gage region 540 in some embodiments. A continuous portion ofthe outermost extent 258 of the cutting element 250 that partiallydefines the cutting profile 505 may define the nose region 520, or atleast a substantial portion thereof, in a manner similar to as describedabove with respect to FIGS. 3 and 4. In some implementations, the noseregion 520 of the cutting profile 505 and the cutting element 250 mayhave the substantially the same radius 522 and perhaps the same centerpoint 524, and thus be co-radial. However, in other implementationswithin the scope of the present disclosure, the outermost extents ofadditional cutting elements 250 and 252 may define a portion of the noseregion 520. For example, multiple blades may each have a cutting element250 coupled thereto at a same radial and axial position, so that themultiple instances of the cutting element 250 may define the nose region520, or at least a portion thereof. In some embodiments, multiplecutting elements 250 may have different radial and/or axial positions,but may nonetheless collectively define the nose region 520, or at leasta portion thereof. In still other embodiments, one or more cuttingelements 252 may be positioned to define at least a portion of the noseregion 520.

In the example implementation depicted in FIG. 5, the outermost extents256 of the cutting elements 252 that don't define the cone region 510 ofthe cutting profile 505 may collectively define the gage region 540 ofthe cutting profile 505, or at least a substantial portion thereof, in amanner similar to as described herein. The cutting elements 252 whoseoutermost extents 256 define the gage region 540 and/or the cone region510 of the cutting profile 505 may be carried by multiple ones of theblades of the bit 500 (e.g., one or more primary and/or secondaryblades). In some implementations, the same blade that carries a largercutting element 250 may not carry the cutting elements 252 that arepositioned closest to the nose region 520 of the cutting profile 505.

In the example implementation shown in FIG. 5, the outermost extents 256of at least twelve (12) cutting elements 252 may define the cone region510 of the cutting profile 505, and the outermost extents 256 of atleast six (6) cutting elements 252 may define the gage region 540. Thesenumbers may, however, vary in other implementations within the scope ofthe present disclosure. For example, the outermost extents 256 of as fewas two (2) cutting elements 252, or as many as thirty (30) cuttingelements 252, may define the cone region 510 and/or the gage region 540.The larger cutting element 250 may have a diameter of twenty-two (22)millimeters, and the smaller cutting elements 252 may have a diameter ofthirteen (13) millimeters, although other dimensions are also within thescope of the present disclosure, including those listed in Table 1,among others.

The number of primary and secondary blades of a bit may also vary withinthe scope of the present disclosure. For example, FIG. 6 is aperspective view of a portion of another example implementation of a bit600. The illustrated bit 600 includes two primary blades 620 and 622 andtwo secondary blades 630 and 632. Drilling fluid flow courses, or junkslots 662, may separate the primary blades 620 and 622 and the secondaryblades 630 and 632.

The distal or downhole ends of the primary blades 620 and 622 may becloser to the central axis of the bit 600 than are the distal ordownhole ends of the secondary blades 630 and 632. Implementationswithin the scope of the present disclosure may also include bits with noprimary blades, such that each blade terminates at a distance from thecentral axis and/or a distal or downhole end of the bit 600. Otherimplementations within the scope of the present disclosure may alsoinclude bits with no secondary blades, such that each blade terminatesat or near the central axis and/or a distal or downhole end of the bit600. The number of primary and secondary blades may also vary within thescope of the present disclosure, from as few as zero (0) or one (1) ofeither type of blade, to as many as four (4), eight (8) or ten (10) ofeither type of blade.

As with other example implementations described herein, the cuttingelements 250 and 252 may be mounted in pockets formed in, or coupled to,the primary blades 620 and 622 and the secondary blades 630 and 632,although other techniques for coupling the cutting elements to the bit600 are also within the scope of the present disclosure. As discussedherein, some embodiments contemplate the cutting element 250 as beingbetween fifteen (15%) and three hundred percent (300%) larger than thecutting elements 252 in diameter, or between one (1) and four (4)industry-standard sizes larger. The dimensions of the cutting elements250 and 252 may, however, vary within the scope of the presentdisclosure, including as set forth in Table 1, among others. Forinstance, in other embodiments, the cutting elements 250 may be moreless than fifteen percent (15%), or more than three hundred percent(300%) larger than the cutting elements 252, or the cutting elements 250may be more than four (4) industry-standard sizes larger than thecutting elements 252.

FIG. 7 is a perspective view of a portion of another bit 700 accordingto some embodiments of the present disclosure. Features other than thecutting elements 250 and 252 are not shown in FIG. 7, although merelyfor the sake of clarity, as those skilled in the art will readilyunderstand in view of the present disclosure that features and/or otheraspects of other bits (e.g., the bits shown in one or more of FIGS. 2-6)may be included, applicable, or readily adapted for utilization in thebit 700 shown in FIG. 7.

The bit 700 may include multiple instances of a larger cutting element250. In such implementations, the larger cutting elements 250 may becarried by different ones of the blades (e.g., different primary blades,different secondary blades, or a combination of primary and secondaryblades). Where the larger cutting elements 250 are each carried by adifferent primary blade, each may be positioned relative to thecorresponding primary blade such that the nose region of the resultingcutting profile is collectively defined by outermost extents of thelarger cutting elements 250. For example, the positions of the multipleinstances of the larger cutting elements 250 may have substantially thesame radial coordinates (relative to radial axis 701) and/or the sameaxial coordinates (relative to bit axis 204), but may have differentazimuth coordinates (e.g., due to being carried by different blades). Inother embodiments, the multiple instances of the larger cutting elements250 may have different radial and axial coordinates, but nonethelessstill collectively define the nose region of the resulting cuttingprofile.

FIG. 7 also demonstrates that the cutting elements 250 and 252 may havevarying back rake and/or side rake within an implementation having oneor more aspects of the present disclosure. Side rake and back rake maybe more easily explained with respect to FIG. 8.

FIG. 8 is a schematic view of a portion of a bit 800, and illustratescutting elements 811-815, 821, 822, and 841-845 rotated into anaggregated profile view and defining a cutting profile 805. Featuresother than the cutting elements and the cutting profile 805 are notshown in FIG. 8, although merely for the sake of clarity, as thoseskilled in the art will readily understand in view of the presentdisclosure that features and/or other aspects of other bits, includingbits described or illustrated herein, may be included, applicable, orreadily adapted for utilization in the bit 800 shown in FIG. 8.

A cone region 810 of the cutting profile 805 may include cuttingelements 811-815, which may each be substantially similar to the cuttingelements 252 described herein or shown in FIGS. 2-7. Multiple instancesof one or more of the cutting elements 811-815 may also be included ondifferent blades. In particular, cutting elements on different bladesmay have the same axial and radial position so as to appear as a singlecutting element 811-815 in FIG. 8. In some embodiments of the presentdisclosure, the radially inner cutting element 811 and the radiallyouter cutting element 815 of the cone region 810 may have substantiallyno back rake and/or substantially no side rake. Thus, in the profileview of FIG. 8, the cutting elements 811 and 815 appear substantiallyround. A medial cutting element 813 may have side rake, or rotationaround an axis 853 that is substantially normal to the adjacent portionof the cutting profile 805. Such rotation may be either clockwise orcounterclockwise. As a result, the medial cutting element 813 may appearelongated in a direction that is substantially normal to the adjacentportion of the cutting profile 805, although the medial cutting element813 may have substantially the same shape as the inner and outer cuttingelements 811 and 815.

Similarly, the intermediate cutting element 812 may have back rake, orrotation around an axis 862 that may be substantially parallel to theadjacent cone portion 810 of the cutting profile 805. An intermediatecutting element 814 may also exhibit back rake, or rotation around anaxis 864 that may be substantially parallel to the adjacent cone region810 of the cutting profile 805. As a result, the intermediate cuttingelements 812 and 814 appear in FIG. 8 to be elongated in a directionsubstantially parallel to the adjacent cone region 810 of the cuttingprofile 805, although they each may have substantially the same shape asthe inner cutting element 811, the middle cutting element 813, the outercutting element 815, or some combination of the foregoing.

The back rake of the intermediate cutting elements 812 and 814 may beeither positive back rake or negative back rake. That is, if the cuttingface of the cutting element 812 and 814 and the surface of the formationor material being cut (e.g., subterranean formation, casing, cement,scale, downhole tools, etc.) form an angle that is greater than ninetydegrees (90°), then that cutting element exhibits positive back rake;whereas, if the angle is less than ninety degrees (90°), then thatcutting element exhibits negative back rake. Thus, if the angle issubstantially equal to ninety degrees (90°), then the cutting elementwould be exhibiting substantially no back rake.

As shown in FIG. 8, a gage region 840 of a cutting profile 805 mayinclude cutting elements 841-845, one or more of which may besubstantially similar to the cutting elements 811-815, or other cuttingelements 252 described herein or illustrated herein. Multiple instancesof one or more of the cutting elements 841-845 may also be included ondifferent blades. The cutting element 841 is shown as being closest tothe nose region 820 of the cutting profile 805, and along with cuttingelement 844 may have substantially no back rake and substantially noside rake. Thus, in the profile view of FIG. 8, the cutting elements 841and 844 appear substantially round. In contrast, cutting elements 842and 845 may exhibit side rake, or rotation around an axis that issubstantially normal to the adjacent gage portion 840 of the cuttingprofile 805. Such rotation may be either clockwise or counterclockwise.As a result, the cutting elements 842 and 845 appear in FIG. 8 to beelongated in a direction that is normal or orthogonal to the adjacentgage region 840 of the cutting profile 805, although they may havesubstantially the same shape as the cutting elements 841 and 844.

Similarly, the cutting element 843 may exhibit back rake, or rotationaround an axis that is substantially parallel to the adjacent gageregion 840 of the cutting profile 805. As a result, the cutting element843 appears in FIG. 8 to be elongated in a direction parallel to thegage region 840 of the cutting profile 805, although the cutting element843 may have substantially the same shape as the cutting elements 841,842, 844, and 845.

The nose region 820 of the example cutting profile 805 depicted in FIG.8 may include cutting elements 821 and 822. The cutting elements 821 and822 may be larger than one or more of the cutting elements 811-815 and841-845. As described herein, implementations within the scope of thepresent disclosure may include multiple instances of smaller and/orlarger cutting elements. Multiple instances of larger cutting elementsmay substantially define the nose region of the resulting cuttingprofile, in the manner described herein. Multiple instances of largercutting elements may be positioned at substantially the same axial andradial coordinates yet differ in azimuth coordinates because they arecarried by different blades. The multiple larger cutting elements mayalso differ with respect to back rake and/or side rake. Thus, while thelarger cutting elements 821 and 822 in the nose region 820 may each havesubstantially circular cutting faces, they appear to be elongated inFIG. 8 as the result of back rake and/or side rake as described herein.As with the smaller cutting elements 811-815 and 841-845, the largercutting elements 821 and 822 may exhibit substantially the same ordifferent back rake, whether positive or negative, and/or may exhibitsubstantially the same or different side rake, whether clockwise orcounterclockwise.

FIG. 9 is a flow-chart diagram of at least a portion of a bit designprocess (900) according to one or more aspects of the presentdisclosure. The process (900) may be utilized to design and produce thebit 200 shown in FIGS. 2 and 3, the bit 400 shown in FIG. 4, the bit 500shown in FIG. 5, the bit 600 shown in FIG. 6, the bit 700 shown in FIG.7, the bit 800 shown in FIG. 8, or other bits within the scope of thepresent disclosure.

In a conventional bit design process, a bit profile may generally bedetermined or designed, and the cutting elements may then be arranged togenerally obtain the designed profile. Each cutting element is typicallythe same size, and that size is also determined by arranging the cuttingelements in a manner that will obtain the desired profile. By utilizinga cutting element in the nose region that is larger relative to cuttingelements in cone, shoulder, or gage regions, a cutting profile accordingto embodiments of the present disclosure can effectively be designed inreverse, such as by first selecting a cutting element for the noseregion and then creating a profile with the nose region of the sizedefined by the selected cutting element.

For example, in the example process (900) shown in FIG. 9, a firstcutting element may be selected (910). As discussed herein, cuttingelements used in a bit may be selected from a set of industry-standardsizes, or custom sizes may be used. Accordingly, selecting the firstcutting element may include selecting the type of the first cuttingelement (e.g., the size, materials, shape, and the like). In accordancewith some embodiments of the present disclosure, the first cuttingelement may be used for the nose region of a cutting profile, and theprocess (900) may therefore also include defining a cutting profile andsetting the radius of a nose region to be substantially equal to and/orco-radial with the radius of the selected first cutting element (920).Defining the cutting profile (920) may therefore also include arrangingthe first cutting element (or multiple first cutting elements) on a bitso as to be positioned co-radial with, or to otherwise substantiallydefine the radius of the nose region. When arranging the first cuttingelement on the bit, the first cutting element may be placed at a singlelocation, or at multiple locations (e.g., at similar radial/axialpositions but at different azimuths corresponding to different blades).

In some embodiments, the defined cutting profile may include one or moreadditional regions in addition to the nose region. Defining the cuttingprofile (920) may therefore also include defining multiple regions ofthe cutting profile (e.g., cone region, shoulder region, gage region,etc.). In some embodiments, the defined cutting profile may includelinear, arcuate, or other cone, shoulder, gage, or other regions, ratherthan a cutting profile with scalloped or undulating regions. Additionaltypes of cutting elements may then be selected and arranged to generallyfollow or approximate the designed cutting profile (e.g., with abest-fit line approximation closely matching the designed profile). Tothat end, the example process (900) may further include selecting thetype of second cutting elements (930) (e.g., size, materials, shape, andthe like) and arranging the second cutting elements to match the gage,shoulder, cone region, or other regions of the profile (940). Selectingthe type of the second cutting elements (930) may include selectingcutting elements that are smaller than the first cutting element and/orselecting multiple sizes of cutting elements. In some embodiments,sizing the second cutting elements (930) and arranging the secondcutting elements (940) may be an iterative process. Optionally, thesecond cutting elements may be at least two (2) industry standard sizessmaller than the first cutting elements. In other embodiments, however,the first and second cutting elements may be the same size, may be oneindustry standard size different, or may otherwise differ, including inmanners discussed herein.

As discussed herein, cutting elements may be placed on multiple bladesof a bit so as to collectively define the cutting profile. As seen withrespect to FIG. 8, for instance, different cutting elements may overlapto define the cutting profile. As will be appreciated in view of thepresent disclosure, such overlap may be due to the rotationallyaggregated view of the profile, and may not include actually placingoverlapping cutting elements on the same blade. Rather, cutting elementswhich overlap (e.g., cutting elements 822, 841, and 842 of FIG. 8) mayeach be arranged on different blades (and at different azimuths) but atthe axial and radial positions corresponding to the cutting profile.Arranging the cutting elements (940) may therefore be performed inthree-dimensional space. Additional factors may also be considered whenarranging the cutting elements. For instance, spacing between differentcutting elements on the same blade may be considered to ensure that ablade can be formed to provide sufficient material to hold a cuttingelement in a corresponding pocket, or sufficient space for anotherattachment mechanism to be used.

In accordance with some embodiments of the present disclosure, theexample process (900) may be implemented using a computing system. Forinstance, a cutting profile may be defined (920) using a softwareapplication executed by one or more processors of a computing system.The shape and other characteristics of the cutting profile may be storedin memory and/or persistent storage. First and second cutting elementsmay also be defined through use of the software application andmanipulated and moved in three-dimensions to define the cutting profile.This may also include defining size, shape, orientation, and number ofblades which support the cutting elements. The three-dimensionalarrangement of the cutting elements and the blades may therefore also besaved by or using the computing system.

In some embodiments, the computing system may also be used to simulateuse of the bit. For instance, a simulation may be run for a designeddrill bit when drilling through a particular type of formation. Asimilar simulation may be run for a milling bit when milling throughcasing to form a window, when milling out a bridge plug, or the like. Asimulation may also be run for an underreamer block defined using aprocess similar to that described above, when expanding a wellborediameter.

Simulations of different designs may also allow for comparisons anditerative modeling. For instance, in a scaling operation, the scaleforms from the outside in, and the nose region of the bit may be incontact with the most scale as it may even contact scale at depthshaving minimal scale formation. The nose region may, in someembodiments, be more vulnerable to damage, delamination, or othermechanical failures resulting from impact forces, shear forces, highertemperatures, shear forces. A simulation system may simulate theseconditions, and bits designed in accordance with embodiments of thepresent disclosure may be simulated to compare effectiveness in removingscale, resistance to damage, and the like. In some embodiments, asimulation or actual run of a bit designed in accordance withembodiments of the present disclosure may show significant resistance todamage as compared to a bit having smaller cutting elements in a noseregion or which uses multiple cutting elements to define the noseregion. For instance, utilizing larger cutters at the nose may improveheat dissipation and/or otherwise provide greater stability, which mayreduce delamination at or near the nose region. Of course, similarsimulations, comparisons, and results may be obtained for other types ofdrilling, milling, underreaming, or other operations, and simulated andactual results of newly designed bits may be compared against otherexisting or newly developed bits.

Accordingly, some embodiments of the present disclosure relate to bitsand other cutting tools that may include a bit body having multipleblades extending therefrom. Each of a plurality of first cuttingelements may be on, in, or otherwise coupled to a corresponding one ofthe blades. One or more second cutting elements may also be coupled tothe plurality of blades and may, with the first cutting elements, definea cutting profile. The second cutting elements may substantially definethe nose region of the cutting profile and may be substantially largerthan the first cutting elements.

In some embodiments, outer extents of the first and second cuttingelements, relative to the bit body and/or axis of the bit body, maydefine the cutting profile. Further, some embodiments contemplate firstand/or second cutting elements each including a substrate and a diamondlayer. In some implementations, one or more first and/or second cuttingelements may have a back rake or a side rake.

In accordance with at least some embodiments, second cutting elementssubstantially defining the nose region may define at least 75% of thenose region, or even 90%. Optionally, the second cutting elements maydefine the full nose region exclusive of the first cutting elements. Atleast some embodiments contemplate at least two second cutting elementscoupled to the blades and located in the nose region. The two secondcutting elements may be positioned at the same axial and radialpositions, but on different blades extending azimuthally from the bitbody.

Cutting elements may have different respective sizes. In someembodiments, the second cutting elements may be at least four (4)millimeters larger than the first cutting elements. In anotherembodiment, the cutting elements may be industry-standard sizes, andthere may be two (2) industry-standard sizes difference between thefirst and second cutting elements. Optionally, the second cuttingelement has a diameter within a range having lower and/or upper limitsthat include any of 15%, 20%, 25%, 30%, 40%, 50%, 60%, 70%, 75%, 80%,90%, 100%, 110%, 125%, 150%, 200%, 250%, or 300% the diameter of thefirst cutting elements, or any value therebetween. In some embodiments,the diameter of the second cutting element may be substantially largerthan each first cutting element outside the nose region.

According to another embodiment of the present disclosure, an apparatusmay include a bit body with multiple blades coupled thereto. A pluralityof cutting elements may be coupled to the blades and may define acutting profile having cone, nose, and gage regions. The cone region maybe nearest a central axis of the body, and the gage region may befurthest from the central axis, with the nose region therebetween. Aradius of the nose region may be substantially equal to a radius of atleast one first cutting element. The cone and gage regions may eachinclude one or more second cutting elements of a diameter different thanthe diameter of the first cutting element.

In some embodiments, the nose region may be substantially co-axial witha first cutting element. The nose region may also have an outer extentsubstantially defining the nose region. Optionally, the first cuttingelements may be three (3) or four (4) or more millimeters larger orsmaller than the second cutting elements. In one embodiment, the firstand second cutting elements may differ by at least two (2)industry-standard sizes. In a particular embodiment, the first cuttingelements may be between 15% and 300% larger in diameter than secondcutting elements. In at least one embodiment, the second cuttingelements are all the same size.

In at least one particular embodiment, two or more cutting elements mayhave the same radial and axial positions on separate blades. Suchcutting elements may be located in the nose, cone, shoulder, gage, orother region of a cutting profile. Further, two or more cutting elementsmay have differing back rake or side rake in some embodiments.

Other embodiments herein may relate to a method for dislodging materialin a wellbore. An example may include moving or otherwise urging a bittoward a downhole end f a wellbore and dislodging material from thewellbore by rotating the bit. The bit may include cutting elements onblades to define a cutting profile as discussed herein. In someembodiments, the cutting elements in a nose region may have a differentsize as compared to cutting elements of other regions of the cuttingprofile and/or the cutting elements of the nose region may be co-radialwith the nose region.

In some embodiments of a method for dislodging material in a wellbore,the dislodge material may include scale. In other embodiments, materialfrom a subterranean formation may be removed. In other embodiments,casing, whipstocks, downhole tools, tubulars, bridge plugs, cement, orother materials may be dislodged.

Another embodiment of the present disclosure relates to designing a bit.In designing the bit, a first size of cutting element may be selected.After selecting the first size, a cutting profile can be created with anose region and one or more other regions. The nose region may becreated to have a radius substantially equal to a radius of the cuttingelement of the first size. A second size for multiple cutting elementsmay be selected and different (i.e., smaller or larger) than the firstsize. The first and second sizes of cutting elements can be arranged onmultiple blades of the bit with the cutting profile, and the first sizedcutting elements may be co-radial with the nose region while the secondcutting elements are arranged in other regions of the cutting profile.

In some embodiments, creating the arrangement may include overlappingcutting elements. A cutting element of the second size may be overlappedwith a cutting element of the first size. Overlapping cutting elementsmay be positioned on different blades. Where multiple cutting elementsof a first size are included, such cutting elements may each be on adifferent blade. The different blades may each be primary blades, eachbe secondary blades, or a combination of primary and secondary blades.

According to some embodiments, designing a bit may include using asoftware application to design the bit in three-dimensions. First andsecond cutting elements may be arranged in three-dimensions alongmultiple blades. A design of the cutting elements may be stored inpersistent storage or memory. The design may be used to simulateoperation of the blade and/or to manufacture a bit. Designing a bit mayalso include positioning cutting elements on a physical bit.

In the description herein, various relational terms are provided tofacilitate an understanding of various aspects of some embodiments ofthe present disclosure. Relational terms such as “bottom,” “below,”“lower, “top,” “above,” “upper”, “back,” “front,” “rear”, “left”,“right”, “forward”, “up”, “down”, “horizontal”, “vertical”, “inner”,“outer”, “clockwise”, “counterclockwise,” and the like, may be used todescribe various components, including their operation and/orillustrated position relative to one or more other components.Relational terms do not indicate a particular orientation for eachembodiment within the scope of the description or claims. For example, acomponent of a BHA that is “below” another component may be moredownhole while within a primary or vertical wellbore, but may have adifferent orientation during assembly, when removed from the wellbore,or in a deviated borehole. Accordingly, relational descriptions areintended solely for convenience in facilitating reference to variouscomponents, but such relational aspects may be reversed, flipped,rotated, moved in space, or similarly modified. Relational terms mayalso be used to differentiate between similar components. Certaindescriptions or designations of components as “first,” “second,”“third,” and the like may also be used to differentiate between similarcomponents. Such language is not intended to limit a component to asingular designation. As such, a component referenced in thespecification as the “first” component may be the same or different thana component that is referenced in the claims as a “first” component.

Furthermore, to the extent the description or claims refer to “anadditional” or “other” element, feature, aspect, component, or the like,it does not preclude there being a single element, or more than one, ofthe additional element. Where the claims or description refer to “a” or“an” element, such reference is not be construed that there is just oneof that element, but is instead to be inclusive of other components andunderstood as “one or more” of the element. It is to be understood thatwhere the specification states that a component, feature, structure,function, or characteristic “may,” “might,” “can,” or “could” beincluded, that particular component, feature, structure, orcharacteristic is provided in some embodiments, but is optional forother embodiments of the present disclosure. The terms “couple,”“coupled,” “connect,” “connection,” “connected,” “in connection with,”and “connecting” refer to “in direct connection with,” “integral with,”or “in connection with via one or more intermediate elements ormembers.”

Although various example embodiments have been described in detailherein, those skilled in the art will readily appreciate in view of thepresent disclosure that many modifications are possible in the exampleembodiments without materially departing from the present disclosure. Aperson having ordinary skill in the art should realize in view of thepresent disclosure that equivalent constructions do not depart from thespirit and scope of the present disclosure, and that various changes,substitutions, and alterations may be made to embodiments disclosedherein without departing from the spirit and scope of the presentdisclosure. Accordingly, any such modifications are intended to beincluded in the scope of this disclosure. Each addition, deletion, andmodification to the embodiments that falls within the meaning and scopeof the claims is to be embraced by the claims. While the disclosureherein contains many specifics, these specifics should not be construedas limiting the scope of the disclosure or of any of the appendedclaims, but merely as providing information pertinent to one or morespecific embodiments that may fall within the scope of the disclosureand the appended claims. Any described features from the variousembodiments disclosed may be employed in combination.

While embodiments disclosed herein may be used in an oil, gas, or otherhydrocarbon exploration or production environment, such environmentsmerely illustrate example environments in which embodiments of thepresent disclosure may be used. Systems, tools, assemblies, apparatuses,methods, and other components discussed herein, or which would beappreciated in view of the disclosure herein, may be used in otherapplications and environments, including in automotive, aquatic,aerospace, hydroelectric, or even other downhole environments. The terms“wellbore,” “borehole,” and the like are therefore also not intended tolimit embodiments of the present disclosure to a particular industry. Awellbore or borehole may, for instance, be used for oil and gasproduction and exploration, water production and exploration, mining,utility line placement, or myriad other applications.

Certain embodiments and features may have been described or claimedusing a set of values defining lower and/or upper limits. It should beappreciated that ranges including the combination of any two values arecontemplated; however, each value is also contemplated as defining anupper limit (e.g., at least 50%) or lower limit (e.g., up to 50%).Endpoints of a range are intended to be included unless expresslydisclaimed. Any numerical value is “about” or “approximately” theindicated value (e.g., the expressions “thirteen (13) millimeters” and“three hundred percent (300%)” are equivalent to the expressions “aboutthirteen (13) millimeters” and “about three hundred percent (300%),”respectively), and takes into account experimental error, manufacturingtolerances, standardized sizing, and other variations that would beexpected by a person having ordinary skill in the art.

The Abstract at the end of this disclosure is provided to allow thereader to quickly ascertain the general nature of some embodiments ofthe present disclosure. It is submitted with the understanding that itwill not be used to interpret or limit the scope or meaning of theclaims.

What is claimed is:
 1. A cutting tool, comprising: a bit body; aplurality of blades extending from the bit body; a plurality of firstcutting elements each coupled to a corresponding one of the plurality ofblades; and a second cutting element coupled to one of the plurality ofblades and defining with the plurality of first cutting elements acutting profile, the second cutting element substantially defining anose region of the cutting profile and being substantially larger thanat least one of the plurality of first cutting elements.
 2. The cuttingtool of claim 1, the plurality of first cutting elements and the secondcutting element each including a substrate and a diamond layer, and atleast one of the plurality of first cutting elements or the secondcutting element exhibiting at least one of a back rake or a side rake.3. The cutting tool of claim 1, the second cutting element defining atleast 75% of the nose region.
 4. The cutting tool of claim 1, the secondcutting element defining at least 90% of the nose region.
 5. The cuttingtool of claim 1, the nose region being defined by the second cuttingelement exclusive of the plurality of first cutting elements.
 6. Thecutting tool of claim 1, further comprising: an additional secondcutting element coupled to one of the plurality of blades and located inthe nose region.
 7. The cutting tool of claim 6, the second cuttingelement and the additional second cutting element being positioned atsame axial and radial positions on different ones of the plurality ofblades.
 8. The cutting tool of claim 1, the second cutting element beingone or more of: at least four (4) millimeters larger than the at leastone of the plurality of first cutting elements; at least two (2)industry-standard sizes larger than the at least one of the plurality offirst cutting elements; or between 15% and 300% larger in diameter thanthe at least one of the plurality of first cutting elements.
 9. Thecutting tool of claim 1, the second cutting element having a diametersubstantially larger than a diameter of each of the plurality of firstcutting elements positioned outside the nose region.
 10. An apparatus,comprising: a bit body; a plurality of blades coupled to the bit body;and a plurality of cutting elements each coupled to a corresponding oneof the plurality of blades, the plurality of cutting elements defining acutting profile having: a cone region nearest a central axis of the bitbody; a gage region furthest from the central axis; and a nose regionbetween the cone region and the gage region, the nose region having aradius substantially equal to a radius of at least one first cuttingelement of the plurality of cutting elements, and the cone region andthe gage region each including at least one second cutting element ofthe plurality of cutting elements that has a different size, shape, orconstruction than the at least one first cutting element.
 11. Theapparatus of claim 10, the nose region being substantially co-axial withthe at least one first cutting element.
 12. The apparatus of claim 10,the at least one first cutting element having an outer extentsubstantially defining the nose region.
 13. The apparatus of claim 10,each of at least one first cutting elements being one or more of: atleast four (4) millimeters different in diameter than each of the atleast one second cutting elements; between 15% and 300% larger indiameter than each of the at least one second cutting elements; or atleast two (2) industry-standard sizes different than each of the atleast one second cutting elements.
 14. The apparatus of claim 10, atleast two of the plurality of cutting elements having same radial andaxial positions on separate ones of the plurality of blades.
 15. Theapparatus of claim 10, at least two of the plurality of cutting elementshaving differing back rake or side rake.
 16. The apparatus of claim 10,each of the plurality cutting elements, except for the at least onefirst cutting element, being of a same size.
 17. A method, comprising:urging a bit toward a downhole end of a wellbore, the bit comprising aplurality of cutting elements collectively defining a cutting profilehaving a nose region between cone and gage regions, a radius of the noseregion equal to, and co-radial with, a first set of one or more of theplurality of cutting elements, and a second set of the plurality ofcutting elements being positioned within the cone and gage regions andhaving a smaller diameter than the first set of one or more of theplurality of cutting elements; and dislodging material from the wellboreby rotating the bit.
 18. The method of claim 19, dislodging materialfrom the wellbore including at least one of: dislodging scale; ordislodging subterranean formation.
 19. The method of claim 19, the firstset of the one or more of the plurality of cutting elements includingmore than one cutting element.
 20. The method of claim 19, the secondset of the plurality of cutting elements including more cutting elementsthan the first set of the one or more of the plurality of cuttingelements.